KR910009701B1 - A method for the continuous forming of felts - Google Patents

Abstract

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Description

Continuous formation method of felt

1 is a cross-sectional perspective view of a felt sample prepared without compression in the longitudinal direction.

2 is a cross-sectional perspective view of a felt sample compressed by the prior art.

3 is a cross-sectional perspective view of a felt sample compressed in accordance with the present invention.

4 is a manufacturing process of the felt according to the present invention.

FIG. 5 is an enlarged detail view of the part in which the felt is compressed in FIG. 4.

6 is a graph showing the compression resistance as a function of capacity for various production methods before and after compression according to the present invention.

7 is a graph showing the improvement of compression resistance as a function of felt thickness.

The present invention relates to a method of forming felt in which fibers are arranged in an irregular direction. In particular, the present invention relates to felt made of mineral fiber represented by conventional names such as glass wool, rock wool and the like.

Conventionally, mineral fiber felt is formed continuously by laminating the fibers carried by the airflow onto a conveyor. The conveyor holds the fibers and also passes gas through the fibers.

The fibers are covered with a dendritic composition that bonds the fibers together before they are laminated on the conveyor, thus providing the cohesion of the felts that are constructed. The dendritic composition applied in liquid form is crosslinked by heat treatment to the felt under preferred conditions of a preselected thickness of capacity.

Conventional felt formation methods produce products in which the properties do not completely meet all requirements suitable for a particular application. In addition to the generally required insulation properties, sometimes the mechanical properties of the products used need to be specified. Examples of this are products that can withstand high compressibility by supporting masonry members (e.g. members used for insulation of commercially obtainable flat roofs) or products used for outdoor insulation, especially those which are resistant to tear stress. .

In order to obtain a product having these characteristics or the following other products, it is necessary to modify the conventional felt forming process.

The formation of a felt that laminates fibers onto a receiving conveyor or similar member results in non-uniform entanglement in all directions. Experimentally it was found that the fibers tended to lie parallel to the receiving surface. The more pronounced this trend is, the longer the fibers are.

This felt structure is also advantageous for insulation and longitudinal pull. Thus, this structure is advantageous for various applications. However, it should be appreciated that such a structure is not best suited, for example, if the product needs to withstand compression or tear in its width direction.

To improve the compression resistance of such felts, the capacity of one solution is increased by increasing the number of fibers per unit surface area on the receiving member from which the felt is formed. Apart from the fact that the fiber mass per unit surface area that can be laminated is limited, the stacking of fibers on the receiving member rapidly impedes the passage of gas, so under good conditions continuous felt formation improves other properties such as tear resistance. I can't let you.

Another solution proposed above is present in such a way that the fiber direction is not already in the plane of the felt but in a right angle plane. This arrangement is made, for example, by molding the pleats on the felt. These corrugations are obtained by stacking the felt in a continuous layer of long or short length to extend in the desired final thickness direction or by compressing the felt in the longitudinal direction.

When the felt is compressed under the above conditions, the waveform is formed. Permanent properties are imparted to the heat treated folded structure of the binder composition carried out next.

The fiber direction oriented in the thickness direction of the thus formed felt makes it possible to substantially improve the compression resistance and tear resistance. However, this structure is disadvantageous for longitudinal endurance, where the felt tends to be unbonded or bent.

The thickness lamination of the fibers is caused by combining felt pieces, widths corresponding to the thickness of the desired felt, where each piece is arranged to be in a plane perpendicular to the surface of the felt constituting the fiber. The pieces are held together by a coating or film covering one or both sides of the felt. If possible these pieces can be directly bonded to each other by their shrinking surface.

Felts (called "laminated fabrics") made by relatively complex techniques are mainly used for insulated pipes. The bending or rolling performance of the product obtained is particularly preferred for this use.

It is an object of the present invention that the mechanical properties, in particular the compression resistance and tear resistance in the thickness direction of the product, do not give rise to any conventional disadvantages, and therefore no wrinkles are formed and the felt is improved without combining the felt pieces with each other. To provide.

Another object of the present invention is to provide a felt which likewise has improved mechanical properties and satisfactory insulation properties.

It is a further object of the present invention to provide a felt of the smallest possible volume while exhibiting the above mentioned properties.

The present inventors have proposed a method for producing at least irregular insulating felt, in which the orientation of the fibers is not isotropic, in order to obtain these results. Instead, the combination of the formation of pleats and felt pieces in the aforementioned technique does not substantially convert the fiber orientation in the felt thickness direction. These fibers are oriented only along the pleat direction of the pieces. On the other hand, according to the invention the innermost fibers of the resulting felt exhibit as many directions as possible with little change in the general orientation of the fibrous layer.

After performing compression in the thickness direction of the felt according to the invention, the fiber felt collected on the receiving member is continuously compressed longitudinally by passing between a series of conveyors forming an upper side and a lower side, wherein the longitudinal compression is This is done by passing from a pair of conveyors running at a certain speed to a pair of conveyors running at low speeds.

It is generally necessary to compress beforehand in the thickness direction. When leaving the fiber receiving chamber, the capacity was found to be quite uneven due to the way the felt is formed. The parts in contact with the conveyor are relatively dense while the fibers appearing on the exposed surface are arranged in a very light and irregular aggregate.

Therefore, the process of compressing the felt in the thickness direction aims to obtain a more uniform capacity even at the point inside the felt thickness under consideration. Satisfactory uniformity is one of the conditions necessary to obtain a satisfactory arrangement of the fibers resulting from longitudinal compression.

Moreover, compression in the thickness direction causes the formation of a fiber dense surface layer similar to that formed on the other surface of the felt in contact with the receiving conveyor.

The retention of the felt and the presence of the surface layer on both surfaces during the longitudinal compression process causes the fibers of the felt inner shaft to rearrange which do not form wrinkles.

Moreover, it has been found experimentally that longitudinal compression should be limited in different processes in order to prevent dense gathering of the fibers obtained within the limited area.

Several factors play a separate role in setting this limit. The capacity of the felt and its thickness need to be particularly taken into account, where to some extent the deformation or bending ability of the felt is determined. It should be noted that high dose thick felts are less likely to form wrinkles. Care should also be taken in the properties of the fibers forming the felt. The shorter the fiber, the easier it is to rearrange without forming wrinkles.

Hereinafter, a representative example of a felt made of mineral fiber and a method of performing this type of process will be described. However, in order to prevent the formation of undesirable wrinkles in the felt commonly used in heat dissipation and sound insulation in this combination, it is advantageous to maintain a compression ratio, that is, a mass ratio per unit surface area before and after each compression, preferably 10 or less, preferably 7 or less. Do.

However, the favorable compressibility varies considerably with the properties of the fibers used in the felt. The coarser the fiber, the lower the angular compression rate. Therefore, for fibers having an average diameter of substantially 10 mu or more, the degree of compression of each process is preferably less than five.

The inventors have found that by this process the fibers initially stacked in a layer almost parallel to the surface of the felt are located along an irregular direction in the felt, while the fibers in contact with the conveyor are almost parallel to the surface. In other words, the roofs formed in the product are relatively small in size relative to the thickness of the felt and do not affect the surface.

Surprisingly, the inventors have found that a higher compression ratio can be obtained when the compression is carried out in several successive steps, in particular a compression that does not form wrinkles is very difficult to perform. The inventors have also found that the properties of the product obtained at the same final compression ratio can be improved when the compression is carried out in several stages. Accordingly, the present invention relates to a method of felt compression carried out in several successive steps.

The reasons for improvement found in the multistage process are not entirely clear. By limiting the compression imparted at each step, it is possible to promote a partial deformation of the limited range, and the following deformation is formed at points other than the first mentioned, so that the deformation is doubled, while the slight deformation in a single step It can also be hypothesized that silver tends to affect a greater amount of felt thickness. This is just a hypothesis. However, examination of the felt cross section confirms this idea: For the present invention, the loops are small and well distributed in the product.

The fibers on the product surface actually form a loopless layer.

Of course, the longitudinal compression ratio that can be obtained when doubling the number of longitudinal compression processes is not infinite. For practical reasons the total longitudinal compression ratio, ie the longitudinal compression performed on the felt, does not exceed 15.

The following describes the various conditions for producing the felt by the method according to the present invention and the obtained felt in detail with reference to the drawings.

Figure 1 shows the predominant position of the fibers in the felt which have been compressed only in the thickness direction. Most fibers are arranged parallel to the felt surface or very dense at the same location. The fiber arrangement is almost the same in either direction when viewed in the longitudinal direction indicated by the arrow and in the transverse direction (for the conveyor on which the felt is formed). This type of felt provides good heat resistance but can be easily compressed or teared in the thickness direction.

As shown in FIG. 2, the corrugated felt provides more heat and compression resistance as long as the corrugation is oriented in the thickness direction of the felt. Deep cuttings appear on the surface of the felt. The cross-sectional structure in the transverse direction changes with the position of the cutting relative to the pleats. This structure has little resistance to flex resistance or longitudinal traction.

3 shows the felt produced by the present invention. Variety of fiber direction in the longitudinal direction appears in the center of the product without wrinkles on the surface. The transverse direction and typically the major direction of the fiber is parallel to the felt surface.

4 shows a process chart for forming a felt. This process chart consists of three main parts: the part from which the felt is formed from the fiber, the part from which the felt is compressed by a method different from the present invention, and the part from which the felt is heat treated to crosslink with the binder.

The felt forming process is shown schematically in the form of three centrifugal units (1). The implementation of the present invention is not limited to any particular method of forming felts. While the methods described above are widely used to form fiber felts on a commercial scale, other methods are commonly used to form rock wool, and also to the peripheral walls where the material is transported and injected into the fiber. It is also particularly important to use an assembly of centrifugal wheels.

Three centrifugal units 1 are arranged in series. In the case of large apparatus, the number of centrifugation units may be 12 or more.

The fibers produced by each centrifugation unit 1 first form an annular void 2. The annular boiler is run by airflow at the bottom of the receiving chamber 3 which is suitable for the gas permeable receiving conveyor 4 holding the fibers. Gas circulation is performed by a vacuum held on the receiving conveyor 4 from the tank 5 in a vacuum relative to the atmosphere in the chamber 3.

The fibers are stacked on the conveyor in increasing thickness until the conveyor reaches the exit from the receiving chamber.

Inside the chamber, a member (not shown) sprays the liquid binder composition onto the fibers. Many studies have been made to uniformly distribute the binder on the fibers, if possible, by spraying the binder evenly throughout the felt.

Typically the felt 6 coming from the chamber 3 is relatively light. The average capacity of the felt is low compared to the significant thickness. Moreover, according to the felt forming method, the fibers are arranged mainly parallel to the conveyor 4. The continuity of deformation results in a substantial increase in the capacity of these felts and changes in the fiber arrangement.

According to the invention this variant preferably comprises a process of compressing the felt in its thickness direction. This compression, for example, as shown in FIGS. 4 and 5, allows the felt to pass between the two conveyors 7, 8 and then in the direction in which the felt runs through the gap separating the two conveyors. By reducing it to

The compressed felt is then passed between the conveyors 9, 10 and 11, 12, and the speed of each pair is made smaller than the conveyor pair to continuously produce longitudinal compression of the felt.

During this continuous deformation the felt is permanently defined to prevent an increase in at least a portion of the initial dose. It is then immediately placed in the oven 13 where heat treatment is performed to crosslink the binder and to stabilize the product.

As soon as it is taken out of the oven 13, the product is cut and packaged according to the intended use.

The treatment of the felt according to the invention is shown in detail in FIG.

5 shows a series of conveyors 7, 9 and 11 which convey the felt until it enters the oven.

The surface of the conveyor carrying the felt is preferably coplanar.

The gratings, meshes or similar structures that make up this gas permeable conveyor are supported on supports such as metal plates or rollers (not shown) in which they are held in a desired position.

The conveyor is driven in the usual way by the drive wheels 14, 15, 16. The conveyor is driven without slips, for example by conveyors and chains, to provide a constant speed to the felt. The motors of each conveyor are separated to allow different settings.

There are three other conveyors 8, 10 and 12 facing each other on the conveyors 7, 9 and 11. In general, the speeds of the conveyor pairs 7, 8, 9, 10, 11, 12 are adjusted to maintain the same traveling speed on both sides of the felt. If one or more conveyors 8, 10 are inclined as shown in the figure, this means that their speed is slightly faster than that of the corresponding conveyors 7, 9.

As described above, the conveyor 9 provides the compressibility of the product thickness as well as the uniformity of capacity at all points throughout this thickness. The fibers also form a surface layer when in contact with the conveyor 9. A slightly faster speed in the conveyor 8 than that corresponding to the progress imparted by the conveyor 7 may promote the formation of the surface layer, and to some extent the fact that rearrangement of the fibers in the felt may be advantageous. It was found experimentally. However, the speeding of the conveyor 8 should be limited because it deteriorates the structure of the felt. Preferably given these process conditions, the overspeed of the upper conveyor 8 should preferably not exceed 10%.

The heights of the conveyors 8, 10, 12 corresponding to the conveyors 7, 9, 11 are adjustable. Also at this end is searched in the chassis shown by conveyors 8, 10 and 12, rollers (not shown) which block them and corresponding motors 17 and 18 which drive them. These chassis 17, 18 are installed by regulating rods 19, 20, 21, 22 from arches 23, 24, 25 supporting the felt forming lines.

The height adjustment of the rods 19, 20, 21, 22 is made by conventional devices (eg screw jacks).

In the structure shown, two conveyors 8, 10 are arranged on the same chassis 17 and are therefore adjusted simultaneously. This constitutes only one possible arrangement. It is advantageous to adjust the inclination and height of the conveyor separately. It is of course also suitable to adjust to another chassis which can be adjusted separately, such as in chassis 17 and 18.

Since the felt must be introduced into the oven, the height adjustment of the different conveyors depends on the thickness of the felt 6 coming from the receiving chamber 3 and the thickness of the final felt. If they are considered purely geometric, the choice of the compression of the felt in the thickness direction depends on the felt behavior on the longitudinal compression phase. The appearance of the desired structural modification depends on the capacitive material of the felt, the thickness and the length of the fiber. Adjusting the height of the conveyor makes it possible to measure the capacity and thickness in the initial thickness of the felt to be processed and the properties of the fibers produced under the most possible conditions.

It should be noted that in this respect the capacity conditions associated with the felt and the workpiece during longitudinal compression are substantially different. In fact, instead, the most commercial product with compression resistance is a relatively large product (insulation product). The dose is usually 30 to 150 kg / cm 2. To achieve this capacity it is common to carry out the final compression in the thickness direction when introducing the material into the binder treatment oven 13. Instead, it is desirable that the capacity of the felt be sufficient to prevent wrinkle formation during longitudinal compression, but this same capacity should not be too high, of course in this case the rearrangement of the fibers is likewise difficult, and partial deterioration of the structure of the felt May result.

As described above, for felts made of fibers having an average diameter of about 6 to 14 microns and an average structure of about several cm, the initial compression in the thickness direction is preferably selected so that the capacity of the compression felt is 10 kg / cm 3 or more. It is preferable.

In lighter felts, the rearrangement of the fibers tends to lower the uniformity, and in order to obtain the product's capacity characteristics, ie compression resistance or tear resistance, it is necessary to increase the longitudinal compression.

Likewise, the compression process is preferably performed on felts whose capacity does not exceed 60 kg / cm 3.

As pointed out above, the felt capacity and compression rate before longitudinal compression vary at least in part. The larger the capacity, the lower the compression ratio.

The corresponding thickness is applied under these conditions. It should be appreciated that in order to rearrange the fibers as described above, the thickness of the felt needs to be minimal during longitudinal compression. In the felt, the thickness before longitudinal compression is preferably 80 mm or more, more preferably 100 mm or more.

The conditions of capacity and thickness can be expressed in terms of fiber mass per unit surface area. In order to proceed simply under satisfactory conditions, it is desirable to make the amount of fibers on the conveyor at least 0.75 kg / cm 3 before longitudinal compression.

In all cases, the compression in the thickness direction is preferably carried out continuously to prevent damage to the fibers. The length of the conveyor 8 is advantageously selected so that the inclination to the surface formed by the conveyor 7 is 20% or less, preferably less than 15%.

If the compression in the thickness direction must be relatively significant to obtain the desired capacity, as shown in FIG. 5, the conveyors 7 and 8 and the conveyors 9 and 10 (the conveyors 9 and 10 have the same chassis). Is installed or not installed at the Therefore, excessive extension of the line can be prevented.

If it is desired to continue to reduce the thickness, it is desirable not to over-prolong the longitudinal compression. It is also desirable to continuously reduce the longitudinal velocity or to extend this process at a slightly slower rate.

Attempts along these process lines have been carried out using a series of rollers moving at slow speeds. These rollers have been found to be very difficult to keep the fibers between the continuous roller and the final fixture in satisfactory conditions.

For this reason, it seems more advantageous to operate with conveyors that can solve this kind of problem. Likewise, it is possible to provide a series of continuous conveyors that continuously feed at decreasing speeds, but from a practical point of view the use of multiple conveyors is practically limited.

The number of felt rate reduction steps is limited to a few, given the allowable compressibility without forming longitudinal wrinkles and surface wrinkles useful for modifying the felt structure. In certain cases, one stage of longitudinal compression is sufficient, while in other cases, it is preferable to perform in two or more stages, as shown in FIG.

In the figure, the felt 6, partially compressed in thickness after passing between the conveyors 7, 8, is introduced between the conveyors 9, 10 present in the extension of the conveyor. The speed of the conveyors 9, 10 is lower than the speed of the conveyors 7, 8. The speed ratio gives the felt a longitudinal compression rate.

After compression through the first to second pairs of conveyors, it is necessary to provide a minimum gap between these conveyors so that the compressed fibers do not leave this gap. In practice, a spacing of several centimeters is sufficient to move the conveyor without the risk of friction and can keep the progress of the felt in the desired direction.

In general, the members that form the runway may provide gaps between the continuous conveyors to provide good continuity for supporting the felt. This member has a flat surface with an extension of the surface between the two conveyors on which the members are arranged.

After passing between the conveyors 9, 10, the longitudinally compressed felt continues to be compressed in its thickness direction, and the second longitudinal compression can pass from the conveyors 9, 10 to the conveyors 11, 12. When it is done.

In two successive compression stages the longitudinal compression ratio may be the same or different. In practice, it is desirable that these compression rates be as close to each other as possible to properly distribute the strains injected into the felt structure as shown above.

In FIG. 5, the conveyors 11 and 12 are arranged parallel to each other. In other words, the felt is no longer compressed in the thickness direction. This is also true if a new compression is performed at the oven inlet. The capacity obtained in the conversion stage of the felt usually requires the application of a relatively considerable pressure that is difficult to handle with the conveyor used in this stage. On the other hand, after being introduced into the oven, the felt passes between two large rollers that can easily apply a high pressure. Nevertheless, it is preferred that the reduction in thickness after being introduced into the oven is not so large that the compression undesirably deforms the felt structure as set by the longitudinal compression step. In fact, it is desirable that the thickness when entering the oven is not more than twice as large as the thickness of the final product.

It is difficult to provide the support continuity of the felt between the conveyors 11 and 12 and the conveyor in the oven without any intermediate due to the pure geometrical properties. In such a case, it is possible to provide the fixing members 26, 27 which likewise form the runway. It is advantageous to heat the member to prevent the fibers from entangled with such a member.

As an example, the test according to the invention is carried out with an apparatus as shown in FIG. 4 to increase the compression resistance of the insulating felt, especially used for flat roofs.

The fibers are formed by centrifugation treatment in a centrifuge where the material is under stretchable conditions. The filaments are formed by passing the material through an orifice located around the centrifuge. These filaments enter hot air flow through the walls of the centrifuge. These filaments are drawn under centrifugal force and are also dropped onto the cold wall where they rupture. The relatively short filaments obtained in this way have an average length of about 1 to 3 cm and a diameter of about 12 microns.

The fibers formed by a series of three centrifuges are coated on phenolic resin and then collected on conveyor felt.

In the felt-forming region, the fiber mass per unit surface area varies depending on the experimental value of 1 to 3 kg / m 2.

The manufactured product varies in thickness from 30 to 120 mm and capacity from 50 to 150 kg / m 3.

The purpose of these tests is to produce compression resistant insulating felt with as little capacity as possible.

6 is the result of the product produced in the state (T) without longitudinal compression, the state in the longitudinal compression (A), and in the state (B) after the two-stage longitudinal compression.

The speeds of the various conveyors used vary so that in a single process the longitudinal compression rate is equal to the compression rate corresponding to two successive processes. The thickness of the comparative product is the same (50mm).

The speed of the conveyor in the felt formation is about 30 m / min. This speed is equivalent to the speed of the conveyor shown in figure 5 (7, 8). (The latter is slightly larger than what is mentioned to incline with respect to the direction of travel of the felt.) The speed in the oven is Varies depending on the dose and is 7 to 10 m / min.

In practice, it is desirable to maintain a significant high speed for the fiber receiving conveyor in order to limit the fiber mass per unit surface area on the receiving conveyor. Many advantages arise from the fact that gas is more easily circulated through the laminated fibers with less thickness. The vacuum effect and the corresponding power ratio to be maintained on the receiving conveyor are substantially reduced. In this respect the longitudinal compression process is preferred because the same final capacity and the speed of the receiving conveyor can be increased.

Considering both cases, the speeds of one intermediate conveyor 9, 10 and the other conveyor 11, 12 are determined as follows: In one compression process, the speed of the conveyor 9, 10 is 35m. It is invariable in / min, and the speeds of the conveyors 11 and 12 and the oven are 7 to 10 m / min. In the two-stage compression process, the speeds of the conveyors 9 and 10 are 18 to 23 m / min, and the speeds of the conveyors 11 and 12 are 7 to 10 m / min.

The height of felt introduction between the conveyors 7, 8 is adjusted slightly larger than the felt. The distance separating the conveyors 9 and 10 at a point where the distance from one point to another is twice the thickness of the final product is 100 mm. The same distance separates the conveyors 11 and 12.

Compression resistance measurements are made in accordance with British Standard BS 2972. According to this standard, measurement samples are compressed to 316 x 316 mm and 100 mm thick. This amount of compression is measured at a compression rate of 10%. The feed rate of the compression plate is 1 mm / min.

FIG. 6, which shows the results in graphical form, shows a sample obtained without longitudinal compression during the formation of the felt, when giving the same compression resistance and requiring the greatest capacity. Divergence for felt samples that performed longitudinal compression is significant at around 15%.

It is surprising that the apparent divergence in the capacity between a single compression sample and a two-stage longitudinally compressed sample is about 10%.

The tests performed to measure the tear resistance of the same product are of the same kind. The felt, which has undergone a two-stage compression stage, is substantially very good. It should be noted that longitudinal compression greatly improves its resistance. Such an improvement may exceed about 100% for an article that has not been treated according to the invention, ie not longitudinally compressed.

According to the invention, the increase in capacity found above is a function of the product thickness. 7 shows the overall change in compression resistance of various products, in particular products having a capacity of 70 to 130 kg / m 2, felt produced in one stage longitudinal compression process (A) or two stage compression process (B).

It should be noted that in this graph, the thickness gradually increases, and after 30 mm it increases considerably, reaching the maximum thickness divergence of more than 50 mm.

Similar tests show the same properties when reproduced with felt made from finer and longer fibers (average diameter 6 μ).

It is clear that this increase is impractical if the dose is very low following this test. A favorable improvement is measured for all glass fiber (or similar) felts, where the capacity is at least 50 kg / m 3.

It has also been found that under the conditions disclosed in the present invention the formation of wrinkles of the felt does not affect the overall thickness of the felt. Therefore, the longitudinal bending resistance in the obtained felt is within the required range from the viewpoint of using the product.

Claims (14)

The fibers carried by the air stream are laminated on a receiving member (the receiving member is gas permeable and retains fibers) to form a felt, and the binder composition is applied to the fibers on the receiving member and compressed in the thickness direction. A method of continuously forming a felt from a fiber of a glass material which crosslinks the binder composition to adhere to a felt structure by heat treating the formed felt, wherein the felt is at least one species formed between the fiber forming step on the receiving member and the heat treatment step. And a compression ratio, that is, a ratio of fiber mass per unit surface area before and after compression is limited to a value less than that in which the formed wrinkles affect the felt surface. The method of claim 1 wherein the longitudinal compression of the felt is carried out in at least a two step continuous process. The method according to claim 1 or 2, characterized in that the longitudinal compression ratio is less than 15 in all longitudinal compression processes. The method of claim 3, wherein the compression ratio is 10 or less in each compression process performed separately. The method of claim 1 wherein the capacity of the felt treated prior to longitudinal compression is at least 10 kg / m 3. The method of claim 1 wherein the capacity of the felt treated prior to longitudinal compression is less than or equal to 60 kg / m 3. The method according to claim 5 or 6, wherein the mass per unit surface area of the felt before longitudinal compression is 0.75 kg / m 3 or more. 3. A method according to claim 2, comprising two longitudinal compression continuous processes, wherein the compression rates of these two processes are about the same. 9. The method of claim 8 wherein the average fiber diameter of the felt is at least 10 microns and the longitudinal compressibility is at most 5 in each process. 10. A felt according to claim 1, 2, 5, 6, 8, or 9, wherein the capacity of the felt is 30 to 200 kg / m 3 by carrying out the compression in the thickness direction before the heat treatment after the longitudinal compression process. Characterized in that At least two pairs of conveyors (7,8) and (9,10) located on the other side of the extension, passing the felt between each pair of conveyors, and separating the two conveyors of the same pair between the two surfaces of the felt And the speed of the conveyor pair is adjusted to reduce the speed of the felt in at least one passing zone from one pair (7,8) to the other pair (9,10). An apparatus for carrying out the method according to claim 10. 12. The apparatus of claim 11, comprising at least three pairs of conveyors 7, 8, 9, 10, 11, 12 between the felt forming region and the heat treatment region, wherein the first pair 7, 8 is felt. Compresses in the thickness direction, performs first direction compression between the first pair (7, 8) and the second pair (9, 10) of the conveyor, and the second pair (9, 10) and the third pair of conveyor Apparatus for performing a second direction compression of the felt between (11, 12). The device according to claim 12, wherein the second pair of conveyors (9, 10) performs compression of the felt in its thickness direction. 14. The runway 26, 27 according to any one of claims 11 to 13, for supporting the compressed felt at the inlet in the heat treatment oven 13 at the extension of the first pair 11, 12 of the conveyor. Providing device.

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